[New developments in RAST studies and their evaluation].

Abstract

New allergen discs for the RAST are now available, such as multi discs with coupled allergens only showing insignificant cross reactivity. They are said to make RAST screening possible, 60 sera with negative RAST results with single allergens and 60 sera with at least one positive RAST result with a single allergen were tested by means of the multi-disc RAST. Negative results with the single allergen discs corresponded to a negative outcome with the multi discs. Sera showing clearly positive RAST with one or more of the single allergens coupled to the multi discs nearly always revealed positive results in the multi-disc RAST. Slightly positive RAST values with one or few single allergens may lead to a negative multi-disc RAST. In addition, we performed alternaria RAST investigations on sera from patients positive to skin tests. We made use of self-made discs coupled with allergens of prick test extracts of seven manufacturers, as well as commercial alternaria discs, either customary or new. Our results proved that the alternaria extracts used for coupling contain different amounts of allergens relevant for the patients. Furthermore, the new alternaria discs revealed clearly better results than those used in former years. The new multi discs and the new alternaria discs, therefore, definitely improve the diagnostic validity of the RAST method.